They seem to be doing OK. I had some ceramic heat insulation cloth lying around which I used. I got this stuff from a NASA supplier and it appears to be working fine. The plastic material in the reflectors can take up to 140 degrees C, and I've only measured 107 on their surface after a one hour ride. My only concern is that they might turn brittle after beeing exposed to those temperatures for a long time. I guess I'll find that out eventually.